A liquid crystal display among many kinds of displays has an advantage of lightness, thinness, low cost, low power consumption for operation, and improved adherence to an integrated circuit and is widely used for laptop computers, monitors, and TV screens.
A liquid crystal display is equipped with a color filter formed by repeating a unit pixel, in which three primary color sub-pixels of red (R), green (G), and blue (B) are combined.
The unit pixel displays a particular color due to the combination of three primary colors when each sub-pixel is adjacently disposed and a color signal is applied to control brightness.
The color filter is made of red (R), green (G), and blue (B) color dyes or pigments. These color materials play a role of changing a white light from a backlight unit into each corresponding color light.
When the color materials have a spectrum with no unnecessary wavelength other than a required absorption wavelength and a smaller absorption band, display performance of the color filter may be improved.
In addition, the color materials are required to have excellent heat resistance, light resistance, and chemical resistance without being faded or discolored when exposed to various conditions such as ultraviolet (UV) radiation, acids, and bases during etching of a color resist.
The color filter can be fabricated using a photosensitive resin composition through various methods such as dyeing, electrophoretic deposition (EPD), printing, pigment dispersion, and the like, in which three or more colors are coated on a transparent substrate.
Recently, the pigment dispersion method has been improved. The pigment dispersion method can provide improved color reproducibility and durability for heat, light, and humidity and thus is becoming more widely adopted.
However, when a pigment-type photosensitive resin composition is used to fabricate a color filter, the color filter can exhibit deteriorated luminance and contrast ratio due to the size and cohesion of pigment particles. To address these problems, there has been research directed to developing a photosensitive resin composition including a dye that is not in the form of particles or has a smaller primary particle diameter than a pigment dispersion. However, dye-type photosensitive resin compositions can have poor heat resistance, light resistance, and chemical resistance and are still not widely commercially available.
Accordingly, there is a need to improve the reliability of the dye-type photosensitive resin composition for commercial availability.